The present invention relates to compressors, and more particularly to variable capacity compressors using a reexpansion type modulating system.
One of the primary objects of the present invention resides in the provision of a capacity modulating system which is infinitely variable between zero modulation and maximum modulation. This is accomplished by utilizing existing lubricating fluid under pressure in combination with a unique arrangement of valves to infinitely control the position of a modulating piston in a reexpansion chamber, thereby establishing the volume of the reexpansion chamber and the degree of modulation. The invention is quite simple and relatively inexpensive in construction, is suited for use with single cylinder or multiple cylinder compressors, is relatively quiet in operation, is more efficient than reexpansion type capacity modulators which operate at only two positions (i.e., maximum or minimum and nothing in between), provides positive control of the modulating piston thereby eliminating the need for return springs, and incorporates means whereby the performance dynamics of the system may be easily changed.
Other advantages and features of this invention will become apparent from the following specification taken in connection with the accompanying drawings.